1. Field of the Invention
This invention relates to a composition for forming an adhesive pattern, a laminated structure obtained by using the same, and a method of producing such a structure. More particularly, the present invention relates to an adhesive pattern-forming composition of a photocurable and thermosetting adhesive possessed of an adhesive function and also a function as a structural member, such as a spacer, a laminated structure of which component members are joined to each other through the medium of a cured product of the adhesive pattern formed by the use of the composition mentioned above and a method of producing the laminated structure. The photocurable and thermosetting adhesive of the present invention is suitable for the formation of the laminated structures in various display devices which require the adhesive pattern as a structural support part (called a spacer, a rib, or a barrier) of a fine pattern and, when a fine pattern is required, also suitable for the formation of the laminated structure electrically connecting other circuit pattern or the electrode of various electronic parts to the fine circuit pattern formed on various substrates, a light reflective part of a back light unit (back lighting device) or the like.
2. Description of the Prior Art
Heretofore, as an adhesive pattern used for the formation of this type of laminated structure, a thermosetting adhesive is generally used. For example, the formation of a light reflective part in a conventional back lighting unit is generally done by preparing ink by mixing a reflective material, such as titanium oxide, in transparent resin varnish as a binder and diluting the resultant mixture with an organic solvent to the viscosity suitable for printing, and applying the ink to the back surface of a light guide plate by screen printing or the like to form a predetermined pattern, such as a dotted pattern, or as disclosed in JP 6-194527 A, by printing a reflecting pattern on one side of a white plastic sheet (reflective material sheet) with ink containing a reflective material and bonding this sheet to a transparent acrylic sheet (light guide plate) by making use of adhesiveness of the formed reflecting pattern itself.
However, in the case of the thermosetting adhesive, since it is necessary to form it into a predetermined pattern by a printing technique, a fine adhesive pattern will be formed only with difficult.
In order to solve such a problem, in recent years a method of forming an adhesive pattern by a photolithography method has been developed and used for the formation of the adhesive pattern in various laminated structures (see JP 3-185086 A, for example). In the case of a photosensitive resin composition to be used for the formation of a photocurable adhesive pattern, however, since it is generally formulated as a composition of (meth)acrylate compound-photopolymerization initiator system, there is a problem that the adhesiveness to a substrate or a laminating sheet member is not sufficient. Moreover, there is much room for improvement in properties of the cured product of the adhesive pattern formed, such as hardness, resistance to heat, and resistance to chemicals.